Oil well pump



tubing from the well bore.

' period of operation.

Patented Jan. 9, 1945 UNITED ,STATES PATENT OFFICE OIL WELL PUMP I Luther B. Rowsey, Houston, Tex. Application December 29, 1941, Serial No. 424,701

11 Claims.

Thisinvention relates to pumps for. deep wells, and more particularly to a construction and technique for protecting the pump plunger of tubing pumps from damage while moving the T same during the lowering thereof to or withdrawing it from the working barrel of the pump.

In the so-called tubing pumps which are commonly used for lifting fluids within wells, a'

plunger which is provided with a traveling valve is lowered through the tubing to the pump barrel which comprises a part of the tubin string. Cups orother sealing means are provided on the plunger to forma seal with the walls of the pump barrel so that upward strokes of the plunger and tubing to the surface withouta'removal of the When the desired repair or replacement has been efiected the plunger assembly and sucker rod string are again lowered in the tubing until the plunger assembly has reached its operating position within the pump barrel. 7

When a, repaired or a new plunger is lowered into a tubing string anymetallic projection, such as metal slivers, will score one or more .of the plunger cups or packing, and such damage may actually prevent operation ofthe pump or may bethe source of incipient failure after a limited .Also, when. the plunger is removed by being I lifted within the tubing a superposed column of fluid is lifted and the pressure produced thereby tends to force the cupsyor other packing, outward ly. and into each annular groove formed by the endsof the tubing sections and the associated ,couplings'. Hence damage is inflicted upon the sealing means during the entire upward trip and M pieces are torn therefrom and fall into the tubing whence such pieces subsequently. enter the pump valves and hence constitute a menace to emcient pumping operations.

Occasionally sucker rods break during pumping operations and under .such circumstances connection is eifected with the broken end by a fishin tool. This end and the plunger assembly are elevated and, since the plunger'is subjected to the hazards above indicated, the com plete assembly is usually removed, as it is assumed that the cups or other packing have been destroyed and must be replaced prior to loweringthe assembly again to pumping position. The present invention contemplates a construction and technique whereby it is possible merely to lift the broken end to the surface, attach the upper portion of the sucker rod thereto and then lower theassembly to pumping position.

It is the primary object of the invention to provide a, pumping mechanism whereby the above mentioned difllculties are eliminated.

Another object is to provide in a pump a plunger shield for protecting the plunger assembly during its travel to or from the pump barrel.

Still another object is to provide a construction whereby the plunger assembly may be lifted any desired distance in the well for connection of a sucker rod thereto and thence lowered to the previous operating position for continued operation.

A further object is to provide a plunger shield for protecting an assembly during travel within a tubing string.

A still further object is to provide in an oil well pump a plunger shield which is capable of effectively removing paraflin from the interior of the tube during movement of the shield therein. It is also an object to provide a tubular plunger shield having flexible longitudinal segments possessing suflicient outward tension to effect thorough cleaning of the walls of the tubing.

Another object is to provide a, plunger shield having a normally expanded end portion adapted to freely receive the plunger to be protected thereby.

A still further object is to provide in an oil well pump a plunger shield which is so constructed that an end portion thereof is contracted during travel within the tubing.

The foregoing objects together with further objects will be more fully ap'parent from the following description taken in connection with the accompanying drawing in which:

Fig. l is a sectional view through a well pump installation showing the plunger assembly closely adjacent the upper end of the pump barrel and within the plunger shield;

Fig. 2 is a sectional view showing the shield in position in the well and the plunger assembly is provided with flexible segments at both the upper and lower ends of the shield.

In Fig. 1 of the drawing there is shown a tubing string I having conventional tube sections 2 and 3 interconnected by means of a collar 4,

there being a slight gap at 5 between these sections. At a desired location within the well there is provided the pump barrel 6 which is of slightly smaller internal diameter than that of the tubing I and which has a carefully prepared inner surface to facilitate movements of and to resist wear by the pump plunger assembly I therein. The coupling 8 interconnects the member 3 and the barrel 6 and has an internal groove 9 which supplements in performing the function which will more fully appear.' p

The pump plunger 1 is of any well known design and includes cups l5 and a traveling valve It. This assembly is attached to the lower end 7 of the sucker red I! which is utilized to move the In Fig. 1 the assembly is shown proximate the upper end of the barrel 6, and'when in this position, the plunger assembly 1 is encased within a shield 20. This shield comprises a tubular member of relatively thin material and has an inwardly extending flange 2| at its upper end so that the plunger assembly cannot slip outwardly from within the shield.

The lower end of the shield 20 is provided with slots 22 and the intermediate segments 23 are tensioned in' a manner that they normally tend to move outwardly slightly so that no difliculty is experienced in causing the assemb y 1 to enter the shield whether such assembly be in position proximate the upper end of the barrel 6 in the ,apparent from the drawing, the thickened portion 24 causes the lower ends of the segments 2-3 ,to be forced inwardly whereby the internal bore of the shield proximate its lower end is tapered, and hence offers a restriction to movement of the assembly I from within the shield.

The thickened portions 24 are ofsuch lineal extent that they will not enter the coupling gaps 5 in the tubing and hence the conditions just described exist at all times during the travel of the assembly in the tubing I. When, however, the assembly I, is lowered to the upper end of the barrel 6, the thickened portions 24 enter the gap between the ends of the section 3 and the barrel 6, such gap including the internal roove 9 in the coupling 8. This condition is illustrated in Fig. 2. When the shield 20 has reached this position the segments 23 move outwardly and the downward movement of the shield is arrested by its engagement with the lower shoulder in the groove 9 or with the upper end of the barrel 6. It. seems apparent that the plunger assembly I is then free to move outwardly from within the shield 20 and into the barrel 6 so that the respective parts are in the positions shown in Fig. 2. V

The operation of the construction seems apparent from the foregoing description. By way of summary, it may be stated that the installaby first placing the shield about the plunger assembly The segments 23 are then pressedinwardly so that the assembly and shield will enter the tubing I whence these elements are lowered upon the sucker rod string I'I. As already explained, the lineal extent of the portions 24 is sufiicient that the segments 23 are urged inwardly at all times during the travel of the assembly and shield within the tubing.

When the shield reaches the position shown in Fig. 2, the plunger assembly moves outwardly.

as just described, into the pump barrelt and thereafter pumping operations are carried out in a normal manner.

If itbe desired to elevate or remove a plunger assembly from within thewell, the sucker rod string I1 is lifted and as the plunger assembly 1 leaves the barrel 6 such assembly enters the shield 20. When the assembly reaches the upper end of theshield a lifting effort is produced thereon and by virtue of the upper tapered surface 21 on the thickened portions '24, the segments 23 are again urged inwardly during the upward travel of the assembly and shield. If the plunger assembly I is merely to be lifted within the tubing and then returnedto pumping position, it seems apparent that this operation can be effected since the shield 20 will move downwardly atany time the sucker rod string H is lowered and in this manner the assembly 1 is at all times protected by the shield 20.

Under some circumstances there is a tendency for sand or other material within the liquid column in the tubing string l to settle and tendto clog the tubing above the shield "20. To avoid difliculty by such sedimentation, a groove 28 may be provided at the upper end of theshield 20, as illustrated in Fig. 3, it being intendedthat the clogging material be bypassed through-this groove by flushing action of liquid longitudinally of the shield 20. -In Figs. 1 and 3 the shield is shown as provided with a leading edge 26 at its lower end to assist in removing paraifin or other material from the walls of the tubing as the shield is lowered therein. Frequently it is desired that'a similar operation be performed as the shield and astion of the plunger within the barrel 6 is effected f5 sembly are lifted within the well. To this end, the shield 20 may be provided with similar upper segments 23, as shown in Fig. 4,.such segments also including thickened areas 24' terminating in an inner tapered surface 25' and leading edge 26'. Since the thickened portions 24' are effective to urge the "segments 23, inwardly, it is apparent that the shield 20 necessarily moveswith the plunger during its travel within the tubing I, except when the shield is moved I to the position shown in Fig.2 or has been with-- used in so-called tubing pumps. Broadly, the

invention comprehends a-hovel construction and technique for protecting a pump plunger from damage during movement within a string of tubing.

.What is claimed is:

upper end of the barrel said shield being a sub stantially tubular structure adapted to surround tially tubular structure adapted to surround the plunger and into and out of which the plunger can move, the lower end of said shield comprising segments tensioned to move resiliently outwardly toward the walls of the tubing, and means for releasably holding the shield proximate the upper end of the barrel so that the pump plunger may move to and from the interior of the shield.

3. A well pump including a flow tubing, a pump barrel attached thereto, a pump plunger in said barrel, and a tubular plunger shield in the tubing proximate the barrel adapted to receive the plunger moving outwardly from Within the barrel,

the lower end of said shield comprising segments normally urged resiliently outwardly into engagement with the walls of the tubing.

4. A well pump including a flow tubing, a pump barrel attached thereto, a pump plunger in said barrel, and a tubular plunger shield in the tubing proximate the barrel adapted to receive the plunger moving outwardly from within the barrel, the lower end of said shield comprising segments normally urged resiliently outwardly into engagement with the walls of the tubing, said segments having outwardly extending projections at their lower ends adapted to urge the segments inwardly during movement of the shield and plunger within the tubing.

5. A well pump comprising a flow tubing, a pump barrel, means interconnecting the tubing and barrel to provide an internal recess therebe tween, a plunger in the barrel, a plunger shield in the tubing, said shield comprising an elon-' gated hollow member into and from which the plunger may move and including a resiliently expansible portion, and means on said portion adapted to enter said recess to releasably hold the shield in position to receive the plunger moving from within the barrel.

6. A well pump comprising a flow. tubing, a pump barrel, means interconnecting the tubing and barrel to provide an internal recess therebetween, a plunger in the barrel, 9. plunger shield in the tubing, said shield comprising an elongated hollow member into and from which the plunger may move and including a resiliently expansible portion, and means on said portion adapted to enter said recess to releasably hold the shield in position to receive the plunger moving from within the barrel, said last mentioned means being adapted to pass slidably past the coupling gaps in the tubing string,

7. A well pump comprising a flow tubing, a

pump barrel, means interconnecting the tubing and barrel to provide an internal recess therebetween, a plunger in the barrel, a plunger shield in the tubing, said shield comprising an elongated hollow member into and from which the plunger may move and including a resiliently expansible portion, and means on said portion X adapted to enter said recess to releasably hold the shield in position to receive the plunger moving from within'the barrel, said last mentioned means comprisingoutwardly extending areas on the expansible portion adapted to pass slidably over the coupling gaps in the tubing string.

8. A plunger shield adapted to surround a well pump plunger assembly during movement into and out of the well tubing string, comprising a tubular member, slots in one end of said member to form resilient segments normally expanded outwardly.

9. A plunger shield adapted to surround a pump plunger assembly during movement of such assembly into and out of the well, a tubing string including a tubular member, oppositely extending slots in said member forming segmented ends thereon, and projections on certain of the segments of said ends engageable peripherally with the well tubing to force the segments inwardly.

10. A well pump plungershield comprising an elongated hollow member open at both ends, one end of said member being resiliently expansible to provide an enlarged opening to the interior of the member.

11. A well plunger shield to enclose and protect the plunger as it is moved in the well comprising an elongated hollow member open at both ends, one end of said member being resiliently expansible to provide an enlarged opening to the interior of the member, and means on the expansible end for causing contracting of said end to a smaller size than the nominal cross section of the remainder of the member.

LUTHER B. ROWSEY. 

